The objective of this research is to continue to investigate membrane mechanisms that underly the myotonic reaction, i.e., abnormal, prolonged, repetitive discharge of action potentials and abnormal contractions of skeletal muscle fibers. Electrophysiological and pharmacological methods will be used to study skeletal muscle responses in the myotonic goat and other naturally myotonic species and in normal muscle of various species after inducing myotonia by chemical agents, ionic changes or other treatments.